You know you're in Japan when...

...you see someone fully normally dressed, but in geta shoes:

...there is a mother and a child both in yukata on the subway train:

...every Japanese person you meet tells you "Teach me English!", instead of "Wanna be friends?"

...minors can get into bars (have yet to see a bar with someone outside/inside to check your age).

...they have festivals where you can win fish, eels, crabs and turtles if you manage to get them.

And so on and so forth =)